Absorption spectroscopy is an analytical technique that can be used to determine the concentration and type of one or more substances in a sample at a sampling interface. Conventional systems and methods for absorption spectroscopy can include emitting light at the sampling interface. As light is transmitted through the sample, a portion of the light energy can be absorbed at one or more wavelengths. This absorption can cause a change in the properties of the light exiting the sample. The properties of the light exiting at the sampling interface can be compared to the properties of the light exiting a reference, and the concentration and type of one or more substances in the sample at the sampling interface can be determined based on this comparison.
Although the comparison can determine the concentration and type of one or more substances in the sample at the sampling interface, the measurements can include a fixed measurement time distribution scheme. In some examples, the fixed measurement time distribution scheme can include an equal distribution of a cycle time to three measurement states: measuring the sample, measuring the reference, and measuring dark. However, the sample signal, reference signal, dark signal, and their corresponding noise levels can differ with operating wavelength, the surrounding environment, and/or measurement location of the substance in the sample. As a result, a fixed measurement time distribution scheme may not be optimal for all operating wavelengths and measurement locations in the sample. Additionally, the fixed measurement time distribution scheme can lead to long measurement times with unimportant information, erroneous measurement data, low signal-to-noise ratio (SNR), or a combination thereof. Thus, methods and systems for dynamically changing the measurement time distribution may be desired. Moreover, high-frequency noise in the system can lead to unacceptable SNR, so methods and systems for removing high-frequency noise may be desired.